1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . T A S K I N G . R E S T R I C T E D . S T A G E S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2012, Free Software Foundation, Inc. -- 10-- -- 11-- GNARL is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This is a simplified version of the System.Tasking.Stages package, 33-- intended to be used in a restricted run time. 34 35-- This package represents the high level tasking interface used by the 36-- compiler to expand Ada 95 tasking constructs into simpler run time calls 37-- (aka GNARLI, GNU Ada Run-time Library Interface) 38 39-- Note: the compiler generates direct calls to this interface, via Rtsfind. 40-- Any changes to this interface may require corresponding compiler changes 41-- in exp_ch9.adb and possibly exp_ch7.adb 42 43-- The restricted GNARLI is also composed of System.Protected_Objects and 44-- System.Protected_Objects.Single_Entry 45 46with System.Task_Info; 47with System.Parameters; 48 49package System.Tasking.Restricted.Stages is 50 pragma Elaborate_Body; 51 52 --------------------------------- 53 -- Compiler Interface (GNARLI) -- 54 --------------------------------- 55 56 -- The compiler will expand in the GNAT tree the following construct: 57 58 -- task type T (Discr : Integer); 59 60 -- task body T is 61 -- ...declarations, possibly some controlled... 62 -- begin 63 -- ...B...; 64 -- end T; 65 66 -- T1 : T (1); 67 68 -- as follows: 69 70 -- task type t (discr : integer); 71 -- tE : aliased boolean := false; 72 -- tZ : size_type := unspecified_size; 73 74 -- type tV (discr : integer) is limited record 75 -- _task_id : task_id; 76 -- _atcb : aliased system__tasking__ada_task_control_block (0); 77 -- end record; 78 79 -- procedure tB (_task : access tV); 80 -- freeze tV [ 81 -- procedure tVIP (_init : in out tV; _master : master_id; 82 -- _chain : in out activation_chain; _task_name : in string; 83 -- discr : integer) is 84 -- begin 85 -- _init.discr := discr; 86 -- _init._task_id := null; 87 -- system__tasking__ada_task_control_blockIP (_init._atcb, 0); 88 -- _init._task_id := _init._atcb'unchecked_access; 89 -- create_restricted_task (unspecified_priority, tZ, 90 -- unspecified_task_info, unspecified_cpu, 91 -- task_procedure_access!(tB'address), _init'address, 92 -- tE'unchecked_access, _task_name, _init._task_id); 93 -- return; 94 -- end tVIP; 95 96 -- _chain : aliased activation_chain; 97 -- activation_chainIP (_chain); 98 99 -- procedure tB (_task : access tV) is 100 -- discr : integer renames _task.discr; 101 102 -- procedure _clean is 103 -- begin 104 -- complete_restricted_task; 105 -- finalize_list (F14b); 106 -- return; 107 -- end _clean; 108 109 -- begin 110 -- ...declarations... 111 -- complete_restricted_activation; 112 -- ...B...; 113 -- return; 114 -- at end 115 -- _clean; 116 -- end tB; 117 118 -- tE := true; 119 -- t1 : t (1); 120 -- t1S : constant String := "t1"; 121 -- tIP (t1, 3, _chain, t1S, 1); 122 123 Partition_Elaboration_Policy : Character := 'C'; 124 pragma Export (C, Partition_Elaboration_Policy, 125 "__gnat_partition_elaboration_policy"); 126 -- Partition elaboration policy. Value can be either 'C' for concurrent, 127 -- which is the default or 'S' for sequential. This value can be modified 128 -- by the binder generated code, before calling elaboration code. 129 130 procedure Create_Restricted_Task 131 (Priority : Integer; 132 Stack_Address : System.Address; 133 Size : System.Parameters.Size_Type; 134 Task_Info : System.Task_Info.Task_Info_Type; 135 CPU : Integer; 136 State : Task_Procedure_Access; 137 Discriminants : System.Address; 138 Elaborated : Access_Boolean; 139 Chain : in out Activation_Chain; 140 Task_Image : String; 141 Created_Task : Task_Id); 142 -- Compiler interface only. Do not call from within the RTS. 143 -- This must be called to create a new task, when the partition 144 -- elaboration policy is not specified (or is concurrent). 145 -- 146 -- Priority is the task's priority (assumed to be in the 147 -- System.Any_Priority'Range) 148 -- 149 -- Stack_Address is the start address of the stack associated to the task, 150 -- in case it has been preallocated by the compiler; it is equal to 151 -- Null_Address when the stack needs to be allocated by the underlying 152 -- operating system. 153 -- 154 -- Size is the stack size of the task to create 155 -- 156 -- Task_Info is the task info associated with the created task, or 157 -- Unspecified_Task_Info if none. 158 -- 159 -- CPU is the task affinity. We pass it as an Integer to avoid an explicit 160 -- dependency from System.Multiprocessors when not needed. Static range 161 -- checks are performed when analyzing the pragma, and dynamic ones are 162 -- performed before setting the affinity at run time. 163 -- 164 -- State is the compiler generated task's procedure body 165 -- 166 -- Discriminants is a pointer to a limited record whose discriminants are 167 -- those of the task to create. This parameter should be passed as the 168 -- single argument to State. 169 -- 170 -- Elaborated is a pointer to a Boolean that must be set to true on exit 171 -- if the task could be successfully elaborated. 172 -- 173 -- Chain is a linked list of task that needs to be created. On exit, 174 -- Created_Task.Activation_Link will be Chain.T_ID, and Chain.T_ID will be 175 -- Created_Task (the created task will be linked at the front of Chain). 176 -- 177 -- Task_Image is a string created by the compiler that the run time can 178 -- store to ease the debugging and the Ada.Task_Identification facility. 179 -- 180 -- Created_Task is the resulting task. 181 -- 182 -- This procedure can raise Storage_Error if the task creation fails 183 184 procedure Create_Restricted_Task_Sequential 185 (Priority : Integer; 186 Stack_Address : System.Address; 187 Size : System.Parameters.Size_Type; 188 Task_Info : System.Task_Info.Task_Info_Type; 189 CPU : Integer; 190 State : Task_Procedure_Access; 191 Discriminants : System.Address; 192 Elaborated : Access_Boolean; 193 Task_Image : String; 194 Created_Task : Task_Id); 195 -- Compiler interface only. Do not call from within the RTS. 196 -- This must be called to create a new task, when the sequential partition 197 -- elaboration policy is used. 198 -- 199 -- The parameters are the same as Create_Restricted_Task_Concurrent, 200 -- except there is no Chain parameter (for the activation chain), as there 201 -- is only one global activation chain, which is declared in the body of 202 -- this package. 203 204 procedure Activate_Restricted_Tasks 205 (Chain_Access : Activation_Chain_Access); 206 -- Compiler interface only. Do not call from within the RTS. 207 -- This must be called by the creator of a chain of one or more new tasks, 208 -- to activate them. The chain is a linked list that up to this point is 209 -- only known to the task that created them, though the individual tasks 210 -- are already in the All_Tasks_List. 211 -- 212 -- The compiler builds the chain in LIFO order (as a stack). Another 213 -- version of this procedure had code to reverse the chain, so as to 214 -- activate the tasks in the order of declaration. This might be nice, but 215 -- it is not needed if priority-based scheduling is supported, since all 216 -- the activated tasks synchronize on the activators lock before they start 217 -- activating and so they should start activating in priority order. 218 -- 219 -- When the partition elaboration policy is sequential, this procedure 220 -- does nothing, tasks will be activated at end of elaboration. 221 222 procedure Activate_All_Tasks_Sequential; 223 pragma Export (C, Activate_All_Tasks_Sequential, 224 "__gnat_activate_all_tasks"); 225 -- Binder interface only. Do not call from within the RTS. This must be 226 -- called an the end of the elaboration to activate all tasks, in order 227 -- to implement the sequential elaboration policy. 228 229 procedure Complete_Restricted_Activation; 230 -- Compiler interface only. Do not call from within the RTS. This should be 231 -- called from the task body at the end of the elaboration code for its 232 -- declarative part. Decrement the count of tasks to be activated by the 233 -- activator and wake it up so it can check to see if all tasks have been 234 -- activated. Except for the environment task, which should never call this 235 -- procedure, T.Activator should only be null iff T has completed 236 -- activation. 237 238 procedure Complete_Restricted_Task; 239 -- Compiler interface only. Do not call from within the RTS. This should be 240 -- called from an implicit at-end handler associated with the task body, 241 -- when it completes. From this point, the current task will become not 242 -- callable. If the current task have not completed activation, this should 243 -- be done now in order to wake up the activator (the environment task). 244 245 function Restricted_Terminated (T : Task_Id) return Boolean; 246 -- Compiler interface only. Do not call from within the RTS. This is called 247 -- by the compiler to implement the 'Terminated attribute. 248 -- 249 -- source code: 250 -- T1'Terminated 251 -- 252 -- code expansion: 253 -- restricted_terminated (t1._task_id) 254 255 procedure Finalize_Global_Tasks; 256 -- This is needed to support the compiler interface. It will only be called 257 -- by the Environment task in the binder generated file (by adafinal). 258 -- Instead, it will cause the Environment to block forever, since none of 259 -- the dependent tasks are expected to terminate 260 261end System.Tasking.Restricted.Stages; 262